I bought a gamo compact in February 2020 and only had a chance to use it a couple of times before everything was shutdown. I was able to start shooting it it again a couple of weeks ago and at first it was fine then 3 weeks ago I pulled the trigger and its just went click. Tried a few more times and it went click every time. After a few attempts it went click and hissed air. Someone put some oil on the piston rod and it started working again. The following week it happened again, put maybe 20 shots through it fine, then click. Some more oil and it was fine.

Today, put around 20 rounds through it and click, hiss.

Each time you tried to dry fire it, it made the normal Pfft of air being released, but as soon as you put a pellet in it, click. When you cocked the pistol, you could not hear any air escaping, it was only after you pulled the trigger that you could hear air releasing.

When I got home I opened up the pistol grip and checked to see what was happening when I cocked the pistol. On the first attempt, click, but i couldnt see anything wrong. However, I just pushed on the sears and springs a little just to make sure they were all seated corrected, tried again and it worked.

What could be wrong? Oil on the piston shouldnt make the sears work and poking the sears shouldnt make a faulty seal work.